Drill shank



Patented June 1923.

. -iuNlT-ED srArs JOHN JAMES v'oorrrrsn or YBrnJHLEHErr, ,PnNNsYLvANIgAssiGnoR-'rofisnrnnnnmi STEEL COMPANY, or BETHLEHEM, rENNsLvnN1A,LA coercitionioisjorjrnivivsrn;`

VANIA. i i

DniLL SHANK.,

Application led March y12, 1921. .Serial No. 4513694.

T o ZZ whom it may concern.'

Be it known that LJOHN JAMES a citizen of the United States and residing at Bethlehem, Northampton'County Stateder the strains of use; to conne any reak age which may take place to' a detachabler member or section instead of anintegral part of the shank and toprovide'a detachable member or section which is of simple construction and which is not only easily applied and removed but is so formed and connected to the other working parts ofthe drill mechanism as to avoid the develop'-v ment of loose-ness or the localization of strains on those parts'lwhich are most likelyv to break 0r giveiway under the strains of use. shank' is made tapering and in' use 4that `shank its' in a tapered collet-or sleeve lof the driving means and at its upper smaller end is provided with a central transversely extending `projecting portion called'ia tang which enters and fits la 'correspondingly shaped bearing opening` at the base of the tapering socket of the driving collet; This tang prevents relative rotation and also acts as a driver and it has been well recognized in the art for many years that in the usual forms used the strains on itare such that it is the ypart of the :mechanism which in nearly all cases gives way rst by breaking or being twisted o. If `it is 'an integral part of the shank the drill must be ydiS- carded permanently or at least for 'a material time untilits shank can be repaired or reshaped. Various'means have been sug# gested to overcome or lessen this trouble vbut without satisfactoryV results since in :most cases some new and unforeseen defect as insuiciently was` introduced by thev changed structure. The' mere ,provision of `a detachable portion of the shank to carry the end tang is not suiiicient for several reasons.

It does not lessen the vstrain on the tangand the liability to' Abreakage andat best merely tends'to make'repair'veasier if the break occurs' on the end tangbut at thel same time Asis well known in the art a drill.

in introduces Athis possibility.; .5f a@ break@ where the 'detachable part joins the main body of the tang and ifithat breaky includes i an integral part-0f lthat'main boldly, thede4 l I tachable part `'does lnot avoidfthe difticulty'.` Furthermorev if. the connection; between the detachablev part` andthe mainbody of'ithe;` shank is not such as to'prevent*relativelon#` gitudinal movement Athe'main part with'iitsi: 'l

drill is likely torgetrloose inthe sleeve or collet .of thev driver an'd'di'opoutv 'as that.

sleeve is -likely'to expand somewhatat'its lower end in bell shapeunderfthe strainsof use andthusa new ytroublel or defect is'in-t troduced; According tofniy invention,` the parts are so formed .andA the ,strains ofuse i.

sol distributed as to not only lessen the strains on lthe Ytang where the breakagejgis most likely to occurbut such that if the break i occurs at the connection betweeny ythe-detach#- able-'partV and' the `main body of the shankV v it will be in the detachable part and not iii themain bod thus permitting the continual useof the dri l by merely'sub'stituting anew' detachabler part.V The structurel isi further# more such that loosenessfof' fit-between the sleeve isfnot likely todevelop; and 'even ifit eoy main body' of yth'eshank andfitsl operating' should, develop the ydrill will stillbefheld.

inplace "for operation and will not droloutfi` The' lnovel feature of Aconstructif'm byzwhich these new results are secured will be more fully understood from the followingfde scriptionand claims" taken in .connection with the drawings. .Inf-the drawings'z-` Fig. l is a longitudinal section of afdrill shank embodying `my "inventionsinf"place' in the rapt/red socket of the driving member; *y

f Fig. '2 isa cross se'ctionthrough the shank on rthe line 2-#2 of Figurer; andzl': l ig.- 3 is a side elevationfofttherdetachable .inemberaloner frIn Figure l voftrhe'drawing Ighave'shown a driving member 10 oi--welll known form which embodiesahtang l1I at its'V upper end for operative connectionf-with` a drilling ma'- chine in afwell knownmanner and-a'sleeve 12 foriningv a taperingorfcoriical` sobketL 13" to f' receive `the tapered shanky of vthe Ydrill'ffandl v i f having-beyond the Iinner end or 'pointof.' .'the

tapered portion ofjthe socket an extension i4 opening thereintoand* havingl 'flatfsides -toi receive andengagethe tang 'onf 'the-"endivef the drill sli-ankstructurer.' V rllhe drill Lkbody '.15 i (partly broken away' in. fthe' n' drawings )ifhas an integral, tapered extension 16 circular in cross section forming the main or fixed portion of the drill shank and it is of such size andvform as to closely fit .in the lower end of-'thesocket 13.but in` the form shown extends only to a point about midway of the length of the socket, as shown in Figure 1. Itsinner or upper end 17 is cut at right angles Ito its axis but is providedwith a transverse groove 18. This groove is so formed that it is widerat its base than at its top or outlet, its sidewalls being outwardly inclined from the end surface 17 to the bottom of the groove preferably atA an angle of Aabout 2O1tothe axis of the shank, as illustrated'in Figure 1, and its side walls also preferably being at anv angle to each other longitudinally making the groove taper 'transversely of the shank and approximately one-thirtysecond inchwider at one end than at the other, as illustrated in Figure 2.

The main features of4 my invention reside in the structure. andarrangement of the detachable member 19 which in use constitutes the inner end of L'the tape-red shank of the drill. It has a conical base or portion 2() at its .larger end of such size and shape as to closely and accurately lit theend walls 17 of the main Ashank portion 16 with its outer surface matching and constituting a continuation of the surface of the main portion 16. It also has transversely thereof at its end a tang or tongue 21 which is transversely and longitudinally tapered at the same angles as the groove 18 and is of such size as to com'- pletely` lill and closely fit said groove being brought into operative relation therewith by relative side movement of the parts l-and 19 with the narrower end of the tang enteringthe wider end of the groove. rl`his gives a wedginaction which makes a tight fit with no o'st motion and in operation the surrounding sleeve 12 maintains that relation preventing relative side movement. Furthermore the transverse taper of the oove 18 and tang 21 making a dovetail Joint secures the parts 16 and 19 together against longitudinal separation and thus there is no possibility that the drill or its shank should separate from the member 19 and drop off-through any loosenes's between it and Ithe sleeve 12 developed by expansion of the sleeve." It will be noted by reference.

to Figure 1 that while the 'base portion 2OA ofthe detachable member 19, like the portion 16, closely tits the inner surface of sleeve 12, this is not true of the part between the line 22 and the smaller` or upper end of member 19 since throughout all of this portion the surfaces are slightly spaced apart and 'are out of contact. This is brought about. by reducing'the diametric measurement or size of the member 19 by a predetermined iixedamount'at and beyond the line 22 fand thus while the taper continues at the same angle from that line to the tip, there is a uniform annular space left around it within sleeve 12. ln other words, the part above line 22 is turned down in` forming` the shank slightly more than the base portion. This arrangement has the advantagethat if or when the outer end of sleeve 12 expands and becomes somewhat bell shaped in use the tapered shank. pants may move forward in the socket sufli-ciently to make a tight tit at the outer end of the socket so as to continue to take some of the strains of use at that point instead of' transferring them to and concentrating them on the smaller tipi portion of the shank. It not only tends to relieve strains on the tang 23 on the inner end of member 19 fitting in the open extension 14.- in the drive member, but also onA the tongue and groove connection between the detachable member 19 and the main shank member 16. It thus lessens the chance for breaking or twisting at other points. It should be noted that the drill and its integral shank portion includes no tang which can be broken or twisted and that since the onlyA tangs used inthe shank are on the detachable member the breakage will in practically all cases be merely in the detachable member. That makes breakage a much'less serious matter since it merely results in a short Stop whilethe broken detachable meniber is removed and a duplicate new one substituted. The substitution may be made easily and quickly since the form of connection is such that a mere blow of the hammer will loosen it and in the same way a mere blow or application ofone home. f Y

'While I have shown one specific embodiment ofmy invention it will'be understood thatit is notconiinedv to that particular form but may include any other embodying those essential elements and features mentionediin the claims. i

Having thus described the invention what is claimed as new and desired to be secured by Letters Patent is: y f

1. A shank for drills comprising a tapered portion integral with the drill adapted to fit in the conical e-nd of the collet. or driving member and having in its end a transverse groove of greater width below its top than at rthe top, and a detachable similarly tapered portion or member having a transverse tangy or tongue on'its larger end adapted to enter said groove from its end and to closely fit-the same and prevent-.relative ro- Itary 0r longitudinal movement of` the portions and a tang on the smaller end adapted to engage the driving member to prevent turning.

2. A shank forpdrills comprising al tapered portion integralwith thedrill adapted to lit` in theconical endof the colletordriving member and having in its end ati-ans,-

pressure will drive thenew p verse groove of greater width -below its top than at the top, and a detachable similarly tapered member having its larger end so shaped as to match and closely fit the end of said integral portion with a tang or tongueclosely tting said groove and a tang on the smaller end the diametric size of said detachable member being reduced a predetermined amount below normal from a transverse line near its larger end to its top whereby above that line it will not in use fit but be spaced from the surrounding conical collet or drive member.

3. An article of manufactureadapted for use as a part of the. tapered shank of a drill comprising a tapered body portion abnormally reduced in diametric size a predetermined amount from a transverse plane shortly above the base or larger end to the upper end, a tang at its lower end tapering transversely from its outer end to its base fo-r connecting it to the shank part of a drill and a tang on its upper end for connection to a driving member.

4. A member adapted to constitute when in use the end of a drill shank comprising a tapered body portion of such diametric size from its small end downwardly throughout most of its length that it will be out of contact with the inner surface of a conical driving member or sleeve fitting the shank be yond it, a tang on its smaller end and a tang on the larger end so shaped as to prevent relative rotaryor lon 'tudinal movement of any part fitting an engaging it.

5. A member adapted to constitute when in use the end of a drill shank comprising a tapered body portion a tang on its smaller end andv a tang or transversely extending tongue on its larger end tapering transversely from its end to its base and tapering longitudinally.

6. A shank for drills comprising a tapered portion integral with the drill adapted .to

t in the conical end of the collet or driving member, and a tapered portion adapted to form a detachable extension of said first mentioned portion within the collet having at its smaller end a tang adapted to engage and enter a socket in the driving member to prevent turning, the meeting ends of said portions of theA shank having transverse tongue and grooveconnection so formed as to permit .the tongue to enter the groove`- from one end but to prevent longitudinal separation of the portions when assembled.

7. A shank for drills comprising a tapered portion integral with'the drill adapted to fit in the conical end of the collet or driving member and a tapered portion adapted to forma detachable extension of said first mentioned portion within. the collet, having 1 at its smaller end a tang adapted to engage and enterv a socket in the driving member to prevent turning, the meetingends of said portions of the shank having transverseV tongue and groove. connection in which thev groove is of greater width below its top I than at the top, .and the tongue matches and fits the groove transversely and both tongue and groove are tapered correspondingly longitudinally thereof and transversely of theshank portions.

8. A shank for drills comprising a tapered portion integral with the drill adapted to t in the conical end of the collet or driving member, and .a detachable similarly tapered member having its larger end so shaped as to match and closely fit the end of 'said` v from the surrounding conical collet or drivel member. n

9. An article of manufacture adapted for use as a part of the'tapered shank of a drill comprising a rigid tapered body portion circular in cross-section abnormally reduced in diametric size a predetermined uniform amount around the peripheryfrom a transverse plane shortly above the base or larger end to the upper end, means at its larger end for connecting it to the shank` part of a drill and a tang on and extending beyond its upper end for connection to a drivingmember. n A In testimony whereof I aflix my signature.

JOHN JAMES COFFEY. 

